The present invention relates to improvement in lamp shades and, more particularly, to collapsible lamp shades which can be folded or rolled for storage and/or shipping and which can be easily installed on a lamp unit.
2. Discussion of the Prior Art
Commercially available lamp shades are generally supplied by the manufacturer in a pre-formed, fully assembled condition. The shade material itself occupies relatively little space, but the assembled shade occupies unduly large amounts of space, most of which is nothing but air. Since shipping and storage space is expensive, the pre-assembly of lamp shades results in greater expense for the manufacturer and retailer, all of which is passed on as higher cost to the consumer.
It has been suggested that storage and shipping expense can be reduced by stacking lamp shades, particularly those shades having some degree of taper resulting in a generally frustoconical configuration. It has been found, however, that stacking tends to damage trim strips, pleating, and other irregular decorative surfaces on the shades. Moreover, merchandising considerations require that certain lamp shades be individually shipped and stored in their own packages for convenient delivery to a customer. Further, when the lamp shades are shipped together with lamp bases, the heavier base can, and often does, cause considerable damage to the more fragile shades when the packages are jostled during shipping.
It is known in the prior art to provide collapsible or knockdown lamp shades which can be rolled or folded into a compact size for shipping and storage. These collapsible shades are intended to be assembled and mounted on a lamp unit by the end user or customer. For example, such collapsible lamp shades are disclosed in U.S. Pat. Nos. 2,819,386 (Linderoth); 3,022,417 (Linderoth); 3,385,963 (Washick); 3,557,362 (White et al); 3,780,287 (Fauri); 4,212,052 (Chambourd); 4,275,434 (Borowitz); and 4,383,291 (Gall); and in French Pat. No. 2,405,427 (Leviel). All of these prior art collapsible shades suffer from one or more of the following disadvantages inherent in their design: (1) difficulty in assembly by the consumer; (2) damage when folded and/or rolled up for storage and shipping; (3) limited possible variation in decorative surface cover and trim; (4) limited possible variation in shade shapes; and (5) inability to retain the intended shape when assembled. Further, many of these prior art designs are capable of use with only one type of shade mounting arrangement, thereby severely limiting the usefulness of such designs as replacement shades.
With respect to disadvantage (1), reference is made to the White et al and Fauri patents wherein strips of plastic, or the like, are provided along the top and bottom edges of the shade cover. Each strip has a circumferential channel adapted to receive a rigid hoop frame to secure the cover to the remainder of the lamp unit. The transverse width of the channel opening (i.e., perpendicular to the plane of the rigid hoop) is smaller than the diameter of the hoop frame wire in order that the frame can be properly retained in the channel when the lamp is fully assembled. As a consequence, the sides of the channel must be resiliently spread during the initial part of the assembly in order to admit one side of the hoop into a portion of the channel. Since the channel depth does not provide diametrical clearance for the hoop in this partially assembled condition, at least one sidewall of the channel (usually the bottom sidewall) must also be resiliently distortable inwardly of the channel so that the remainder of the hoop can forcibly bend with sidewall into the channel while that side of the hoop is being snapped into the channel. This procedure has proven difficult for many consumers. Moreover, the requirement that one or both sidewalls of the channel be made of resiliently deformable material, permitting opening and closing of the channel during the assembly operation, is in partial conflict with the requirement that the material be sufficiently rigid to retain the hoop in the channel during use. Add to this the fact that the shade is to be stored and shipped in a rolled or folded position, requiring deformation of the channel transversely of the channel length. It can be seen from these diverse requirements that the choice of material for the channel-defining material becomes somewhat limited. Quite often the transverse bends and folds effected during storage/shipping produce permanent deformations in the strips. As a consequence, it has been proposed that the channel strips be shipped and stored disassembled from the shade cover and then attached to the cover by the consumer at the time of assembly. This additional assembly step, however, is disadvantageous since it has proven too difficult for many consumers, particularly if the attachment is to be permanent in nature. It the atachment is not permanent, inadvertent detachment and resulting collapse of the shade is a real possibility. Apart from all of these difficulties, it must be remembered that these prior art collapsible shades have hoop-receiving channels at both the upper and lower edges of the shade, and that manipulation of the shade during insertion of the lower hoop can bring about disengagement of the upper hoop, or vice verse.
Some of the noted above difficulties are addressed by the Gall patent wherein the hoop receiving channel opening is wider than the hoop wire diameter, and wherein the channel depth provides sufficient diametrical clearance to enable the initially inserted portion of the hoop to be pushed deep within the channel while the remainder of the hoop is worked into the remainder of the channel. Tapering of the channel walls automatically centers the inserted hoop. This structure eliminates the need to deform the channel sidewalls during insertion; however, since the channel sidewalls require no deformation during assembly, it stands to reason that no such deformation is required for disassembly. As a consequence, the hoop and shade cover can become inadvertently dissociated from one another when the lamp is jostled or otherwise disturbed as may be the case during dusting, movement, or even actuation of the lamp unit. In addition, the channel strip in the Gall patent is subject to permanent deformation when folded or rolled for shipping or storage. Finally, the working of the hoop into the bottom channel can readily dislodge the hoop from the top channel, and vice versa, making assembly a somewhat cumbersome procedure.